Paphiopedilum concolor (LindL. ex Bateman) Pfitzer var. trungkienii aver., O. Gruss, C. X. Canh et N. H. Tuan, new variety of well known species from northern Vietnam

1 Leonid V. Averyanov Komarov Botanical Institute, Russian Academy of Science,St. Petersburg, Prof. Popov Str. 2, Russia 

2 Olaf Gruß In der Au 48, 83224 Grassau, Deutschland

3. Nguyen Hoang Tuan, Dep. of Pharmacognosy, Hanoi university of Pharmacy, 15 Le Thanh Tong, Hoan Kiem, Hanoi, Vietnam E-Mail: tuandl50@yahoo.com 

4. Chu Xuan Canh, 92 Thanh Nhan Street, Hai Ba Trung District, Hanoi, Vietnam e-mail: cxcanh@gmail.com

Summary: A new variety of Paphiopedilum concolor from Vietnam is described as Paphiopedilum concolor (LindL. ex Bateman) Pfitzer var. trungkienii aver., O. Gruss, C. X. Canh et N. H. tuan. The variety distinctly differs from all known infraspecific taxa of Paph. concolor in sepals, petals and lip speckled with unclear more or less dull purple-violet blotches particularly well visible on lateral petals. It also has a subquadrate to obovate staminode apically truncate with a prominent triangular, acute tooth. In its overall shape the staminode of the new variety well differs from other known forms of Paph. concolor. Like subalbino forms it has leaves almost lacking purple on their lower surface.

Paphiopedilum concolor is well known lovely ornamental plant spreading in cultivation all over the World. This beautiful miniature slipper orchid was described in 1889 on the base of cultivated plants originated from peninsular Myanmar (Type: Burma, cult. Rucker, Parish). It has rather large area of the natural distribution in SE Myanmar, S. China, Thailand, Laos, Vietnam and Cambodia. In intact habitats not disturbed by human activity this species often very common and plays significant role in lithophytic herbaceous plant communities. As any widespread species this orchid is very variable along large area of its distribution particularly in variation of leaf markings and flower color scheme. Many more or less well segregated infraspecific taxa in rank of subspecies, varieties or forms are listed in a number of monographic treatments (Cribb, 1998; Averyanov et al., 2003, 2004; Averyanov, 2008; Liu Zhongjian et al., 2009). Among them - forms lacking purple spots on the flowers (f. album, var. immaculatum); forms lacking purple color on lower leaf surface (f. chlorophyllum); forms with narrow and long petals (f. longipetalum); forms with purple-streaked petals (f. striatum); subalbino forms lacking almost all anthocyane pigments (f. sulphurinum); forms with 4- or 5-flowered inflorescence (f. regnieri); forms with particularly large median sepal (f. tonkinense) and some others (Cribb, 1998; Liu Zhongjian et al., 2009). Some of these deviating forms are treated as subspecies or varieties. One new, very distinct form of P. concolor was recently found in addition to already known wide species diversity. This unusual plant treated in present paper as a new, locally endemic variety was discovered by Vietnamese orchid enthusiast – Mr. Nguyen Hoang Tuan in lowland limestone area of northern Vietnam. This plant is described below as Ptrz. concolor var. trungkienii.

Type: NORTHERN VIETNAM, 2 May 2017, Chu Xuan Canh & Nguyen Hoang Tuan, C.X.Canh 107 (LE, holotype). Type voucher herbarium specimen was prepared from cultivated plants collected in northern Vietnam, Thai Nguyen province, Dong Hy district, evergreen broad-leaved forest on rocky limestone at elev. 500–600 m a.s.l., June 2015, Ngo Trung Kien, sine №. Epitype: d-EXSICCATES OF VIETNAMESE FLORA 0278/C.X.Canh 107 © L.Averyanov. (Fig. 4).

Description. Perennial lithophytic or occasionally terrestrial rosulate clustering herb with (2)3–5(6) distichous leaves. Roots rather fleshy, wiry densely brown hairy. Leaves oblong to elliptic, rounded and minutely emarginate at apex or with short unequal roundish lobes, (5)6–10(12) cm long, (2)2.2–2.6(2.8) cm wide, upper surface contrastly tessellated with dark and pale light greenish, dull pale green or dull green with light purple-violet tint below. Inflorescence 1–2 flowered; peduncle up to (2.5)3-4(5) cm long, heavily dull, dirty-purple spotted, shortly white pubescent. Floral bracts ovate, (1)1.2-1.6(1.8) cm long, (0.8)1-1.2(1.4) cm wide, conduplicate, green, spotted with purple near base, white ciliate along margin. Flowers, well opened, (5)5.5-6(6.5) cm in diameter, sepals, petals and lip yellowish-white to dull yellow, more or less speckled with unclear more or less dull purple-violet blotches, shortly white pubescent. Dorsal sepal broadly ovate to almost round, roundish to emarginate at apex, (2.4)2.6-2.8(3) cm long and wide. Synsepal with slightly reflexed margins, ovate, with blunt or roundish apex, (2.2)2.4-2.6(2.8) cm long, (1.6)1.8-2(2.2) cm wide. Petals elliptic, slightly oblique, blunt or roundish at apex, (3.4)3.6-3.8(4) cm long, (2.2)2.4-2.6(2.8) cm wide. Lip narrowly ovoid, ellipsoidal or fusiform, (3.2)3.4-3.6(3.8) cm long, (1.3)1.4-1.6(1.8) cm wide, fleshy, with incurved margins. Staminode triangular obovate, truncate at apex, with large triangular acute tooth at middle, glabrous, (6.5)7-9(9.5) mm long, (5.5)6-8(8.5) mm wide. Stigma white to light yellowish, glabrous, almost round 5-6 mm in diam. Column short, cylindrical, 2-3 mm long, 4-5 mm in diam., white pubescent. Anthers subglobular, 1.5-2 mm in diam., pollen viscid, dark olive-brown. Ovary narrowly fusiform, (2.4)2.8-3.2(3.4) cm long, (4)4.5-5.5(6) mm in diam., obscurely triangular in transversal section, dark green, shortly white pubescent, bent at apex.

Etymology. New variety is named after its discoverer Mr. Ngo Trung Kien.

Habitat and phenology. Primary and secondary broad-leaved evergreen forests on rocky, limestone at elevations 500–600 m a.s.l., lithophytic rosulate herb on steep rocky slopes and cliffs. Flowering in May.

Distribution. Central part of northern Vietnam (Thai Nguyen province, Dong Hy district). Local endemic of lowland limestone areas of central part of northern Vietnam.

Notes.

Described plant distinctly differs from all known infraspecific taxa of P. concolor in sepals, petals and lip speckled with unclear more or less dull purple-violet blotches particularly well visible on lateral petals. It also has subquadrate to obovate staminode apically truncate with prominent triangular, acute tooth which. In its overall shape staminode of our plant well differs from other known forms of P. concolor. Like subalbino forms our plant has leaves almost lacking purple on lower surface.

Flowers of P. concolor var. trungkienii in their color scheme slightly resembles flowers of P. godefroyae (God.-Leb.) Stein from Malacca Peninsula, but having larger, somewhat obscure dull blotches on petals. It also may be close to P. bellatulum (Rchb.f.) Stein from the northern Thailand and to Chinese P. wenshanense Z.J.Liu et J.Yong Zhang having similar spotted flowers and somewhat similar floral morphology. The primarily observed differences of newly discovered plant looks quite significant and further studies may indicate specific status of this plant.

Literature cited

Averyanov L., P. Cribb, Phan Ke Loc, Nguyen Tien Hiep. 2003. Slipper Orchids of Vietnam. With an Introduction to the Flora of Vietnam. Compass Press Limited, Royal Botanic Gardens, Kew. 308 p.

Averyanov L., Cribb P., Phan Ke Loc, Nguyen Tien Hiep. 2004. Lan Hai Viet Nam (Slipper Orchids of Vietnam). 308 pp. Giao Thong van tai Publishing house, Ho Chi Minh City (Vietnamese ed.).

Averyanov L. 2008. The orchids of Vietnam. Illustrated survey. Part 1. Subfamilies Apostasioideae, Cypripedioideae and Spiranthoideae. Turczaninowia, 11, 1: 5-168.

Cribb P. 1998. The Genus Paphiopedilum. Natural History Publications, Kota Kinabau. 427 p.

Liu Zhongjian, Chen Singchi, Chen Lijun, Lei Sipeng. 2009. The genus Paphiopedilum in China.

Science Press, Beijing. 371 pp.